Percussion-fuse for explosive shells.



E. GATHMANN.

PERCUSSION FUSE FOR EXPLOSIVE SHELLS. APPLICATION FILED OCT. 16,1917.

l 296,28l Patented Mar. 4, 1919.

.-I TTORNEY,

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' y m' Y Vthe city of Baltimorelin the State of Mary- EMIL GATHMANN, OF BALTIMORE, MARYLAND PERCUSSION-FUSE FOR EXIELOSIVE SHELLS.

Specification of Letters Patent. Patented Mar, 4, 1919,

Application led October 16. 1917. Serial No. 196,788.

containing the primer or ignition cap 5, and a. communicating passage 6 from said ignition cap to the magazine chamber. To the rear of the said diaphragm 4 is located the firing hammer chamber 7, which atits rearward end has a contracted portion 8.4 At right angles to the longitudinalaxis of said contracted portion 8 are these being enlarged at their upper endsas shown at 10. A firing or ignition .hammer or plunger 11 is placed within the chamber 7, said firing hammer being provided with a firing point 12 at its forward end and a contracted neck portion 13 at its rearward end, the contracted neck portion having a collar 14 at its rearward end. Detents or lock bolts 15 are located within the detent chamber 9 and forced downwardly against the contracted neck portion 13 of the iiring hammer 11 Iby means of springs or the like devices 16, said springs being given suitable compression by means of detent chamber covers or disks 17, which are firmly secured by friction or otherimeans in the enlarged portion 10 of the upper ends of the detent chamber. A creep or retaining spring 18 is placed in the chamber 7 to normally locate the firing hammer 11 in the rearward portion of the chamber 7, so that same is engaged with the shoulder19, a clearance space 20 being provided between the rear end of the contracted chamber 8 and the enlarged portion 14 of the contracted stem 13 so that bearing does not take place at this point between the hammer and the stock of the fuse. r1`he diaphragm 4 is provided with a valve 21, which normally v`closes the vent or communicating passage 6, the said valve being kept inthe closed position, by means of a` spiral spring or like device 24. The valve 21 has an annular recessed portion 22 and is normally located in chamber 23 so that this recess 22 is directly over and opening into the vent 6; the gases due to any premature explosion of cap 5 will thus discharge into the said recess 22 and thence into the valve chamber 23, the gases being prevented from entering vent '61 by reason of the sealing action of the head of the valve 21 against the shoulder in the bottom of the valve chamber 23, as clearly shown in Fig. l of the drawing.

The spring 24 is kept under suitable tension by means of a plate or disk 17, firmly seated in an enlarged portion 10 of the valve chamber 23, the said valve chamber 23, as

To all whom it may concern:

Be it known that I, EMIL GATHMANN, a citizen of the United States, residing in land, have invented certain new and use Improvements in Iercussion-Fuses for EX- plosive' Shells, of which the following is a specification. 4

This invention' relates to improvements in percussion fuses, and has for its object the prevention of premature or accidental explosion of the shell to which the fuse is fitted, while at the same time providing means for the prompt operation and firing of the fuse when fitted to a shell iired from a rifle gun, upon impact of said shell with a target of even light or medium resistance to penetration by the shells.

This invention-primarily relates to fuses of the type known to those skilled in the art as centrifugal arming, and is similar in basic principles to that shown in U. S. Patent No. 672,826, granted jointly to Louis and Emil Gathmann on April 23rd, 1901.

In the present invention I have greatly simplified and cheapened the construction of the fuse without sacrificing any of the safety features or efficiency of the fuses as a prime exploder for the shell. I have also adapted the construction so that the same may be employed in the United States standard sizes of fuse stock for medium and large calibershells without any increase in the weight or size of the fuses over that at the present time adopted as a service standard.

In the accompanying Adrawings Figure 1 is a longitudinal section of a fuse stock with my improved type of frin hammer or exploder and the restraining lIietents shown in elevation. Fig. 2 is a section on line 2-2 of Fig. 1 with the detents shown in elevation. Fig. 3 is an elevation of a fragmentary portion of the fuse stock. Fig. 4 is a side elevation of the securing plate or disk for the detents or valves before same is secured in its seat.

' In said figures, 1 represents the stock of the fuse and 2 the threaded portion thereof for securing the fuse within the base portion of the shell. A cavity 3 is provided at the forward end of the fuse in which is placed the boosteror magazine charge of explosive material in the usual manner of fuses of-:this type. To the rear of this cavity is placed a threaded diaphragm or plug 4,

detent chambers 9,

previously stated, connecting with' the vents 6 and 61, the vent 61 being in a different plane from `the vent y6, as shown in the drawings. A. cover plate or disk 25 is provided to close the chamber 3 inthe usual nianner, well known to those familiar with the art. A

Describing now the operation of my percussion fuse, the 4fuse being assembled as shown, is mounted. by threads 2, preferably within the base'portion of the shell, the shell beingloaded with explosive material. When the shell has'clearedl the riied gun from VYwhich it was fired it has attained a rapid whirling motion about its longitudinal axis, due to the riiing of thebarrel of the' gun, and by reasonfof such revolving motion, centrifugal action or force is generated and the detents 15 and valve 21I will be thrown radially outward and held in such outward position by the said centrifugal force duri g the `flight or trajectory of the shell. The firing hammer or exploder 11 will thus be free to move forward upon any impact of the projectile with a resisting target, as the enlarged portion 14 of thje reduced neck-like stem 13 of the hammer 11 will not meet anybbstructions tending to retard saidrforward or axial motion of the plunger, excepting the light action of the creep spring 18, which is readily overcome by the inertia of the hammer upon impact During the even with very light targets. first shock of discharge of the projectile the inertia of the plunger, as Well as that of the detent and valve, as shown in Fig. 1, will 12 of the firing hammer and 61 being then keep these various elements in a locked or normali position', but during the flight of the projectile or-immediately after leaving the bore of the gun the detents will assume the position as shown in Fig. 2. When the projectile strikes al target the firing point I 11 will.' impact against ythe detonator or primer cap 5, and cause the same to explode, and the vent 6 open and clear, the explosive material contained in the magazine chamber' 3 will likewise be exploded, this magazine charge in turn ignitingand exploding the bursting charge of the shell.

In the construction as shown the detent chambers run at approximately right angles through. the threaded portion of the stock of the fu`se and are cyllndrical in shape, as shown 1n`F1g.'3, as are likewise the enlarged the detent chamber.

n order to obtain a firm, seating of` the cover plates 17 an economical manner and without^`the use of any considerable space, the platesy are preferably shaped as shown in Fig. 4' (171) so that the plates will detent chamber 9,v

enter Vfreely within the portion 10 of said and upon being pressed so, asvshown in Figs. 1 e plates are enlarged in diameter iat lor ractically and,J 2, th

and a close itting frictionfit is readily obtained between the edges of said plate 17 and the side walls of the said recess 10.

The spring tension holding thedetents and valve should be such that there will be ample reserve force in case of accidental misplacement of said detents due to accidental drop of the shell from practically any height within reason, but should be of such resiliency that they will readily open due to the rapid rotary motion imparted by the shell and contained fuse stock by the rifling action ,of the gun when the shell is red from same. Tests" have been made with these fuses and show that they are absolutely safe upon being dropped as high as ft. and impacting on heavy plates, and that they will arm in a gun when litted to a projectile ydischarged with a velocity between 2,000 and 3,000 ft. seconds. Obviously, some of the features of construction may be modified, as I have described a fuse stock which is mainly suitable for being fitted to the projectile at its base end. The same elements might, however, be applied to a fuse fitted to 'other portions of the projectile, for instance, at the nose or front end, or I might leave out the valve mechanism in the anvil disk and use the ordinary straight type of vent in the anvil disk or any other detonating or primer cap holding device.

What'I claim is: A l. In a percussion fuse adapted to be carried by yan lexplosive projectile, a cham- -bered fuse stock, in combination with a relatively iixed anvil therein, a primer secured on one sidef of said anvil, a firing hammer, means for normally holding saidl hammer out of contact with the primer, an axial .vent extending from the said primer into the valve chamber, a radially inclined vent colmnunicating from an end portion of the valve chamber to a booster chamber, and a valve within said valve chamber normally interposed between said axial and radially inclined vents, said valve being arranged to open ya passage between the said vents upon projection of a projectile carrying the said percussion fuse from a cannon.

2. In a percussion fuse adapted to be carried by, an explosive projectile, a chambered fuse stock, .in combination with a relatively ixed anvil therein, a primer secured on one end of said anvil, a firing hammer, means for normally holding said hammer out of contact withv Ithe primer, an axial vent extending from the said primer into an annular passage' in a valve chamber, a radially inclined vent communicating from an end portion of said .valve chamberto abooster charge chamber,'and -a valve within said valve chamber normally interposed between said axial and radially inclined vents, and

llf

gases in case of a premature explosion of said primer, said valve being arranged to open a passage between said vents upon projection of a projectile carrying the said percussion fuse from a cannon.

3. In a percussion fuse adapted to be carried by an explosive projectile, a chambered fuse stock, in combination with a relatively fixed anvil therein, a primer secured on one side of said anvil, a iiring hammer, means for normally holding said hammer out of contact with the primer, an axial vent extending from said primer -into the valve chamber, a radially inclined vent communicating from an end portion of the valve ch'ambervto a booster charge chamber, and a valve within said chamber normally interposed between said axial and radially inclined vents, said valve being arranged to open a passage between said vents upon rapid axial rotation of a projectile carrying the said percussion fuses.

4. In a percussion fuse adapted'to be carried by an explosive projectile, a chambered fuse stock, in combination with a relatively fixed anvil therein, a primer secured on one side of said anvil, a firing hammer, means for normally holding said hammer out of contact with the primer, an axial vent extending from said primer toward a valve chamber, a relatively inclined vent communic-ating from an end portion of the valve chamber to a booster charge chamber, and a valve within said chamber normally interposed 'between said axial and relatively inclined vents, said valve being arranged to open a passage between said vents upon rapid axial rotation of a projectile carrying said percussion fuses.

5. In a percussion fuse adapted to be carried by an explosive projectile, a ohambered fuse stock, in combination with a relatively fixed anvil therein, a primary ignition cap secured on one side of said anvil, a ring hammer, means for normally holding said hammer out'ofV contact with the primary ignitio-n cap, an Iaxial vent extending from said primary ignition cap toward a valve chamber, and a valve Within said chamber normally interposed between said axial vent and a vent communicating with a primary booster charge chamber, the axes of said vent communicating with the booster charge chamber being relatively inclined tothe cross sectional diameter of the said valve chamber, the said valve being arranged to open a passage between said vents uponprojection of a projectile carrying the said percussion fuse from a gun.

In testimony whereof I have signed my name to this specification.

EMIL GATHMANN. 

